Electric guitars are often equipped with a moveable bridge, sometimes referred to as a tremolo or a whammy bar. Conventional tremolo systems, such as the tremolo used on the Fender Stratocaster guitar sold under the trademark STRATOCASTER™, have conventional tuners, and a conventional nut. Refinements to the conventional tremolo have been made, such as with the Floyd Rose locking system sold under the trademark FLOYD ROSE™. With such a system, the strings use conventional tuners for rough tuning, then the strings lock at the nut. Such a system prevents movement and binding of the strings within the nut. Fine tuners are provided to allow further tuning after the nut has been locked.
In either conventional tremolo system, the posts (also known as studs) that hold the tremolo in place are threaded into anchors that are embedded in the body of the guitar. The anchor makes a physical connection with the wood of the guitar body and has inner threads that allow the height of the posts to be adjusted with the anchors. Adjusting the height of the posts changes the height of the tremolo from the guitar body, which in turn changes the action of the guitar. However, the movement of the posts within the tolerances of the threads can cause the overall tuning of the guitar to be less than desirable. Additionally, movement of the posts back and forth within the tolerances of the threads can cause the anchor, over time, to form an elongated hole within the wood of the guitar. In severe cases, the elongation may be so drastic that the anchor may pull out of the wood with little or no force at all, initiating a trip to a guitar repair shop.
One conventional system used to securely hold the posts and the anchors is to install a small set screw through the middle of the post. The set screw makes contact with the bottom of the anchor to secure the threads of the post to the threads of the anchor. However, not all guitar anchors have a bottom portion that a set screw can connect with. In such a system, there is nothing for the set screw to hold against, other than the wood of the guitar. Having a set screw touch the wood of the guitar does not ensure a snug fit and may damage the wood of the guitar body. Furthermore, posts containing set screws are expensive, may be difficult to locate and may not be available for every type of thread.
One solution to create a secure fit when using bottomless anchors is to first use a flat piece of metal or hard plastic with a thread that can be adjusted with a screwdriver. Such a piece is placed into the anchor first. After making a rough adjustment, the post is secured inside the anchor creating a snug fit. However, such a system has limited flexibility in adjusting the height of the post after the initial installation. Such a lack of adjustment makes the initial setup of a guitar tedious. Also, since guitars are normally adjusted on a periodic basis, the lack of fine tuning of the height of the post is a disadvantage. Another approach would be to simply remove the existing anchor, and replace it with a new anchor and a post with a set screw. However, such a modification requires expertise in removing the old anchor without damaging the finish of the guitar.
It would be desirable to retrofit an existing anchor and post system with a device that would allow securing the post to the anchor, yet still provide fine height adjustments through varying the height of the post.